U.S. patent number 11,054,233 [Application Number 16/632,831] was granted by the patent office on 2021-07-06 for hydraulic time delay actuated by the energetic output of a perforating gun.
This patent grant is currently assigned to Hunting Titan, Inc.. The grantee listed for this patent is Hunting Titan, Inc.. Invention is credited to Johnny Covalt, Joseph Albert Henke.
United States Patent |
11,054,233 |
Henke , et al. |
July 6, 2021 |
Hydraulic time delay actuated by the energetic output of a
perforating gun
Abstract
A mechanical gun to gun delay for providing a desired time delay
between the firing of a first gun and the firing of a second gun
downhole without using a pyrotechnic fuse as the delay.
Inventors: |
Henke; Joseph Albert
(Hallettsville, TX), Covalt; Johnny (Burleson, TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hunting Titan, Inc. |
Pampa |
TX |
US |
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Assignee: |
Hunting Titan, Inc. (Pampa,
TX)
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Family
ID: |
1000005659178 |
Appl.
No.: |
16/632,831 |
Filed: |
July 25, 2018 |
PCT
Filed: |
July 25, 2018 |
PCT No.: |
PCT/US2018/043725 |
371(c)(1),(2),(4) Date: |
January 21, 2020 |
PCT
Pub. No.: |
WO2019/023363 |
PCT
Pub. Date: |
January 31, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200166320 A1 |
May 28, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62536830 |
Jul 25, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F42C
9/06 (20130101); E21B 43/11855 (20130101); F42D
1/06 (20130101); E21B 43/117 (20130101) |
Current International
Class: |
F42C
9/06 (20060101); F42D 1/06 (20060101); E21B
43/1185 (20060101); E21B 43/117 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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9001103 |
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Feb 1990 |
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WO |
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2017139656 |
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Aug 2017 |
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WO |
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Other References
Notification of Transmittal of the International Search Report and
the Written Opinion of the International Searching Authority, PCT
Application No. PCT/US18/43725, dated Oct. 11, 2018, 9 pages. cited
by applicant .
Communication with Supplementary European Search Report based on
EP18837382.3 dated Mar. 30, 2021, 7 pages. cited by
applicant.
|
Primary Examiner: Semick; Joshua T
Attorney, Agent or Firm: McKeon; Christopher Saunders; Jason
Arnold & Saunders
Parent Case Text
RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application
No. 62/536,830, filed Jul. 25, 2017.
Claims
What is claimed is:
1. A mechanical delay comprising: a first perforating gun; a first
cylindrical body located downhole from and coupled to the first
perforating gun, having a first inner bore with radial break plugs
disposed therein, a communication piston located uphole from the
radial break plugs; a second cylindrical body coupled to and
located downhole from the first cylindrical body having: a second
inner bore; a first cylindrical piston slidably disposed therein
with a face exposed to the first inner bore of the first
cylindrical body; a first rod coupled to and located axially
downhole from the first cylindrical piston; a second cylindrical
piston located downhole from and coupled to the first rod and being
slidably disposed within the second inner bore, the cylindrical
piston having a first face and a second face, with a thru bore
located transversely between the first face and the second face; a
second rod located downhole from and coupled to the second
cylinder; hydraulic fluid located between the second rod and the
second inner bore; and wherein explosive energy from the first
perforating gun causes the communication piston to fracture the
radial break plugs, thus flooding the first inner bore with
wellbore fluid and forcing the combination of first cylindrical
piston, first rod, second cylindrical piston, and second rod
downward, thus causing the hydraulic fluid located in the second
inner bore to meter through the transverse thru bore of the second
cylindrical piston.
2. The apparatus of claim 1 further comprising the first
cylindrical body having one or more ports located radially and
connecting the first inner bore with the outside of the first
cylindrical body.
3. The apparatus of claim 1 further comprising a firing sub coupled
to and located downhole of the second cylindrical body containing a
ball retaining rod coupled to a firing pin located axially
proximate to a percussion detonator.
4. The apparatus of claim 1 wherein the firing sub is further
adapted to accept a booster and detonating cord combination
proximate to the percussion detonator.
5. The apparatus of claim 1 wherein the firing sub further coupled
to and located uphole from a second perforating gun.
6. The apparatus of claim 1 further comprising the thru bore having
a orifice disposed therein adapted to meter hydraulic fluid.
7. The apparatus of claim 6 wherein the orifice is a JEVA jet.
8. A method for creating a firing delay between two perforating
guns comprising: detonating a first perforating gun; transferring
energy from the first perforating gun to a first sub containing a
break plugs blocking thru ports; converting the transferred energy
into momentum in a piston; breaking the break plugs with the
piston; flooding the first sub; acting on a piston assembly within
a second sub using wellbore fluid causing it to translate downward;
metering the speed of the piston assembly translation using
hydraulic fluid passing through a sized orifice; engaging the
piston assembly against a firing head sub; and detonating a second
perforating gun using the firing head sub, wherein the metering of
the speed of the piston assembly using hydraulic fluid causes a
desired time delay between the detonating of the first perforating
gun and the second perforating gun.
9. The method of claim 8 further comprising shearing pins holding
the piston assembly in place.
10. The method of claim 8 further comprising metering the hydraulic
fluid using an orifice.
11. The method of claim 10 wherein the orifice is a JEVA jet.
12. The method of claim 8 further comprising a detonating cord and
booster supplying the energy from the first perforating gun.
13. The method of claim 8 further comprising the firing head sub
igniting a detonating cord and booster assembly coupled to the
second perforating gun.
14. A hydraulic delay apparatus comprising: a housing 106 having a
frangible communication piston bore 154, a fluid communication bore
155, a working piston bore 170, and a hydraulic delay bore 145,
each aligned axially with each other and the housing 106, the
housing 106 also having ports 107 opening fluid communication
between an area outside the housing 106 and the fluid communication
bore 155; a frangible communication piston 133 positioned within
the frangible communication piston bore 154, the frangible
communication piston having a frangible element too large to pass
through frangible communication piston bore 154 and adapted to
break when exposed to an explosive input; at least one frangible
port plug 135 positioned within and sealing the at least one port
107; a working piston 101 within working piston bore 170 and having
a top side exposed to the fluid communication bore 155; a middle
rod 105 attached at a top end to the working piston 101 opposite
the top side of the working piston; a hydraulic delay piston 112
within hydraulic delay bore 145 and attached to a bottom end of
middle rod 105 at a top side of hydraulic delay piston 112, the
hydraulic delay piston having a flow restrictor 134 allowing fluid
communication between the top side and a bottom side of hydraulic
delay piston 112; a bottom rod 104 attached at a top end to the
bottom side of hydraulic delay piston 112; wherein hydraulic delay
bore 145 is filled with a hydraulic fluid, frangible port plug 135
is adapted to be broken by frangible communication piston 133 and
allow fluid to flow through port 107 once broken; and wherein a
wellbore fluid entering the fluid communication bore 155 through
ports 107 applies pressure to the top side of working piston 101,
which applies force to the hydraulic delay piston 112 through
middle rod 105 causing the hydraulic fluid to flow through the flow
restrictor 134 to the top side of hydraulic delay piston 112
allowing hydraulic delay piston 112 to move downward relative to
housing 106.
15. The apparatus of claim 14 wherein the flow restrictor is a JEVA
style jet.
16. A hydraulic delay apparatus comprising: a housing having a
frangible communication piston bore, a fluid communication bore, a
working piston bore, and a hydraulic delay bore, each aligned
axially with each other and the housing, the housing also having at
least one port opening fluid communication between an area outside
the housing and the fluid communication bore; a frangible
communication piston positioned within the frangible communication
piston bore, the frangible communication piston having a frangible
element too large to pass through frangible communication piston
bore and adapted to break when exposed to an explosive input; at
least one frangible port plug each positioned within and sealing a
respective port of the at least one port; a working piston within
working piston bore and having a top side exposed to the fluid
communication bore; a middle rod attached at a top end to the
working piston opposite the top side of the working piston; a
hydraulic delay piston within hydraulic delay bore and attached to
a bottom end of middle rod at a top side of hydraulic delay piston,
the hydraulic delay piston having a flow restrictor allowing fluid
communication between the top side and a bottom side of hydraulic
delay piston; a bottom rod attached at a top end to the bottom side
of hydraulic delay piston; a hydraulic firing head coupled to and
located downhole of the housing and further containing a ball
retaining rod coupled to a firing pin located axially proximate to
a percussion detonator, wherein the firing sub is further adapted
to fire a perforating gun coupled proximate and adjacent to the
percussion detonator; wherein the hydraulic delay bore is filled
with a hydraulic fluid, the at least one frangible port plug is
adapted to be broken by frangible communication piston and allow
fluid to flow through the respective port of the at least one port
once broken; and wherein a wellbore fluid entering the fluid
communication bore through the at least one port applies pressure
to the top side of working piston, which applies force to the
hydraulic delay piston through middle rod causing the hydraulic
fluid to flow through the flow restrictor to the top side of
hydraulic delay piston allowing hydraulic delay piston to move
downward relative to housing.
17. The apparatus of claim 16 wherein the flow restrictor is a JEVA
style jet.
Description
BACKGROUND OF THE INVENTION
Generally, when completing a subterranean well for the production
of fluids, minerals, or gases from underground reservoirs, several
types of tubulars are placed downhole as part of the drilling,
exploration, and completions process. These tubulars can include
casing, tubing, pipes, liners, and devices conveyed downhole by
tubulars of various types. Each well is unique, so combinations of
different tubulars may be lowered into a well for a multitude of
purposes.
A subsurface or subterranean well transits one or more formations.
The formation is a body of rock or strata that contains one or more
compositions. The formation is treated as a continuous body. Within
the formation hydrocarbon deposits may exist. Typically a wellbore
will be drilled from a surface location, placing a hole into a
formation of interest. Completion equipment will be put into place,
including casing, tubing, and other downhole equipment as needed.
Perforating the casing and the formation with a perforating gun is
a well known method in the art for accessing hydrocarbon deposits
within a formation from a wellbore.
Explosively perforating the formation using a shaped charge is a
widely known method for completing an oil well. A shaped charge is
a term of art for a device that when detonated generates a focused
explosive output. This is achieved in part by the geometry of the
explosive in conjunction with an adjacent liner. Generally, a
shaped charge includes a metal case that contains an explosive
material with a concave shape, which has a thin metal liner on the
inner surface. Many materials are used for the liner; some of the
more common metals include brass, copper, tungsten, and lead. When
the explosive detonates the liner metal is compressed into a
super-heated, super pressurized jet that can penetrate metal,
concrete, and rock. Perforating charges are typically used in
groups. These groups of perforating charges are typically held
together in an assembly called a perforating gun. Perforating guns
come in many styles, such as strip guns, capsule guns, port plug
guns, and expendable hollow carrier guns.
Perforating charges are typically detonated by detonating cord in
proximity to a priming hole at the apex of each charge case.
Typically, the detonating cord terminates proximate to the ends of
the perforating gun. In this arrangement, a detonator at one end of
the perforating gun can detonate all of the perforating charges in
the gun and continue a ballistic transfer to the opposite end of
the gun. In this fashion, numerous perforating guns can be
connected end to end with a single detonator detonating all of
them.
The detonating cord is typically detonated by a detonator triggered
by a firing head. The firing head can be actuated in many ways,
including but not limited to electronically, hydraulically, and
mechanically.
Expendable hollow carrier perforating guns are typically
manufactured from standard sizes of steel pipe with a box end
having internal/female threads at each end. Pin ended adapters, or
subs, having male/external threads are threaded one or both ends of
the gun. These subs can connect perforating guns together, connect
perforating guns to other tools such as setting tools and collar
locators, and connect firing heads to perforating guns. Subs often
house electronic, mechanical, or ballistic components used to
activate or otherwise control perforating guns and other
components.
Perforating guns typically have a cylindrical gun body and a charge
tube, or loading tube that holds the perforating charges. The gun
body typically is composed of metal and is cylindrical in shape.
Within a typical gun tube is a charge holder designed to hold the
shaped charges. Charge holders can be formed as tubes, strips, or
chains. The charge holder will contain cutouts called charge holes
to house the shaped charges.
It is generally preferable to reduce the total length of any tools
to be introduced into a wellbore. Among other potential benefits,
reduced tool length reduces the length of the lubricator necessary
to introduce the tools into a wellbore under pressure.
Additionally, reduced tool length is also desirable to accommodate
turns in a highly deviated or horizontal well. It is also generally
preferable to reduce the tool assembly that must be performed at
the well site because the well site is often a harsh environment
with numerous distractions and demands on the workers on site.
Currently, perforating guns are often assembled and loaded at a
service company shop, transported to the well site, and then armed
before they are deployed into a well. Sometimes perforating guns
are assembled and armed at the well site. Because the service
company shop often employs a single gun loader, maintaining close
control on the gun assembly/loading procedures can become
difficult. Accordingly, quality control on the assembled/loaded
guns may be improved by reducing the amount of assembly necessary
at the service company shop.
Many perforating guns are electrically activated. This requires
electrical wiring to at least the firing head for the perforating
gun. In many cases, perforating guns are run into the well in
strings where guns are activated either singly or in groups, often
separate from the activation of other tools in the string, such as
setting tools. In these cases, electrical communication must be
able to pass through one perforating gun to other tools in the
string. Typically, this involves threading at least one wire
through the interior of the perforating gun and using the gun body
as a ground wire.
SUMMARY OF EXAMPLE EMBODIMENTS
An example embodiment may include a mechanical delay comprising a
first perforating gun, a first cylindrical body located downhole
from and coupled to the first perforating gun, having a first inner
bore with a radial break plugs disposed therein, a communication
piston located uphole from the radial break plugs, a second
cylindrical body coupled to and located downhole from the first
cylindrical body having a second inner bore, a first cylindrical
piston slidably disposed therein with a face exposed to the first
inner bore of the first cylindrical body, a first rod coupled to
and located axial downhole from the first cylindrical body, a
second cylindrical piston located downhole from and coupled to the
first rod and being slidably disposed within the second inner bore,
the cylindrical piston having a first face and a second face, with
a thru bore located transversely between the first face and the
second face, a second rod located downhole from and coupled to the
second cylinder, a hydraulic fluid located between the second rod
and the second inner bore, and wherein explosive energy from the
first perforating gun causes the communication piston to fracture
the radial break plugs, thus flooding the first inner bore with
wellbore fluid and forcing the combination of first cylindrical
piston, first rod, second cylindrical piston, and second rod
downward, thus causing the hydraulic fluid located in the second
inner bore to meter through the transverse thru bore of the second
cylindrical piston.
An alternative embodiment may include the first cylindrical body
having one or more ports located radially and connecting the first
inner bore with the outside of the first cylindrical body. A firing
sub may be coupled to and located downhole of the second
cylindrical body containing ball retaining rod coupled to a firing
pin located axially proximate to a percussion detonator. The firing
sub may be further adapted to accept a booster and detonating cord
combination proximate to the percussion detonator. The firing sub
may further be coupled to and located uphole from a second
perforating gun. The thru bore may have an orifice disposed therein
adapted to meter hydraulic fluid. The orifice may be a JEVA
jet.
An example embodiment may include a method for creating a firing
delay between two perforating guns comprising detonating a first
perforating gun, transferring energy from the first perforating gun
to a first sub containing a break plugs blocking thru ports,
converting the transferred energy into momentum in a piston,
breaking the break plugs with the piston, flooding the first sub,
acting on a piston assembly within a second sub using wellbore
fluid causing it to translate downward, metering the speed of the
piston assembly translation using hydraulic fluid passing through a
sized orifice, engaging the piston assembly against a firing head
sub, and detonating a second perforating gun using the firing head
sub, wherein the metering of the speed of the piston assembly using
hydraulic fluid causes a desired time delay between the detonating
of the first perforating gun and the second perforating gun.
An alternative example embodiment may include shearing pins holding
the piston assembly in place. It may include metering the hydraulic
fluid using an orifice. The orifice may be a JEVA jet. A detonating
cord and booster may supply the energy from the first perforating
gun. The firing head sub may ignite a detonating cord and booster
assembly coupled to the second perforating gun.
An example embodiment a hydraulic delay apparatus comprising a
housing having a frangible communication piston bore, a fluid
communication bore, a working piston bore, and a hydraulic delay
bore, each aligned axially with each other and the housing, the
housing also having ports opening fluid communication between an
area outside the housing and the fluid communication bore, a
frangible communication piston positioned within the frangible
communication piston bore, the frangible communication piston
having a frangible element too large to pass through frangible
communication piston bore and adapted to break when exposed to an
explosive input, at least one frangible port plug positioned within
and sealing the at least one port, a working piston within working
piston bore and having a top side exposed to the fluid
communication bore, a middle rod attached at a top end to the
working piston opposite the top side of the working piston, a
hydraulic delay piston within hydraulic delay bore and attached to
a bottom end of middle rod at a top side of hydraulic delay piston,
the hydraulic delay piston having a flow restrictor allowing fluid
communication between the top side and a bottom side of hydraulic
delay piston, a bottom rod attached at a top end to the bottom side
of hydraulic delay piston, wherein hydraulic delay bore is filled
with a hydraulic fluid, frangible port plug is adapted to be broken
by frangible communication piston and allow fluid to flow through
port once broken, and wherein a wellbore fluid entering the fluid
communication bore through ports applies pressure to the top side
of working piston, which applies force to the hydraulic delay
piston through middle rod causing the hydraulic fluid to flow
through the flow restrictor to the top side of hydraulic delay
piston allowing hydraulic delay piston to move downward relative to
housing. The flow restrictor may be a JEVA style jet.
An example embodiment may include a hydraulic delay apparatus
comprising a housing having a frangible communication piston bore,
a fluid communication bore, a working piston bore, and a hydraulic
delay bore, each aligned axially with each other and the housing,
the housing also having ports opening fluid communication between
an area outside the housing and the fluid communication bore, a
frangible communication piston positioned within the frangible
communication piston bore, the frangible communication piston
having a frangible element too large to pass through frangible
communication piston bore and adapted to break when exposed to an
explosive input, at least one frangible port plug positioned within
and sealing the at least one port, a working piston within working
piston bore and having a top side exposed to the fluid
communication bore, a middle rod attached at a top end to the
working piston opposite the top side of the working piston, a
hydraulic delay piston within hydraulic delay bore and attached to
a bottom end of middle rod at a top side of hydraulic delay piston,
the hydraulic delay piston having a flow restrictor allowing fluid
communication between the top side and a bottom side of hydraulic
delay piston, a bottom rod attached at a top end to the bottom side
of hydraulic delay piston, a hydraulic firing head coupled to and
located downhole of the housing and further containing a ball
retaining rod coupled to a firing pin located axially proximate to
a percussion detonator, wherein the firing sub is further adapted
to fire a perforating gun coupled proximate and adjacent to the
percussion detonator, wherein hydraulic delay bore is filled with a
hydraulic fluid, frangible port plug is adapted to be broken by
frangible communication piston and allow fluid to flow through port
once broken, and wherein a wellbore fluid entering the fluid
communication bore through ports applies pressure to the top side
of working piston, which applies force to the hydraulic delay
piston through middle rod causing the hydraulic fluid to flow
through the flow restrictor to the top side of hydraulic delay
piston allowing hydraulic delay piston to move downward relative to
housing. The flow restrictor may be a JEVA style jet.
BRIEF DESCRIPTION OF THE DRAWINGS
For a thorough understanding of the present invention, reference is
made to the following detailed description of the preferred
embodiments, taken in conjunction with the accompanying drawings in
which reference numbers designate like or similar elements
throughout the several figures of the drawing. Briefly:
FIG. 1 depicts a cross section of an example embodiment in its
initial configuration before activating the mechanical delay.
FIG. 2 depicts a cross section of an example embodiment in its
final configuration after the mechanical delay has been
activated.
FIG. 3 depicts a cross section of an alternative example embodiment
in its initial configuration before activating the mechanical
delay.
DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION
In the following description, certain terms have been used for
brevity, clarity, and examples. No unnecessary limitations are to
be implied therefrom and such terms are used for descriptive
purposes only and are intended to be broadly construed. The
different apparatus, systems and method steps described herein may
be used alone or in combination with other apparatus, systems and
method steps. It is to be expected that various equivalents,
alternatives, and modifications are possible within the scope of
the appended claims.
An example embodiment is shown in FIG. 1 of a hydraulic variable
time delay sub 100. This sub performs the task of a pyrotechnic
delay fuse by using mechanical motion instead of a chemical
reaction. In this design there is a communication sub 106 that is
coupled to and located below a first perforating gun. An alignment
insert 109 that is slidably disposed in the first bore 153 of the
communication sub 106 accepts the end of a detonating cord with a
booster from the first perforating gun. A shear grooved cap 110 is
located between the alignment insert 109 and the communication
piston 133. Communication piston 133 is substantially cylindrical
and slidably disposed within the second bore 154 of the
communication sub 106. Communication piston 133 may be a frangible
communication piston that shears at the shear grooved cap 110 when
a proximate located booster is fired. The communication sub 106 has
one or more ports 107 for putting the third bore 155 in fluid
communication with the wellbore when the delay sub 100 is
activated. Break plugs 135 prevents fluid communication in the
initial starting configuration shown in FIG. 1.
A meter sub 102 is coupled below the communication sub 106. The
meter sub 102 houses a working piston 101 held in place by within
the working piston bore 170 of sleeve 111 and threaded to a middle
rod 105 which is further threaded to a hydraulic delay 112, which
is then further threaded to a bottom rod 104. This allows for the
working piston 101, middle rod 105, hydraulic delay 112, and the
bottom rod 104 to slide upwards and downwards in unison within the
inner bore 145 of the meter sub 102. A firing head housing 115, in
this case an industry standard firing head commonly used with
perforating guns, is coupled below the meter sub 102. The volume
160, defined by the hydraulic delay 112, the hydraulic fluid bore
145, the bottom rod 104, and the firing head housing 115 create a
hydraulic fluid chamber, volume 160, storing hydraulic fluid.
Initially installed, the combination of working piston 101, middle
rod 105, hydraulic delay 112, and the bottom rod 104 are located as
far upward as possible to store the maximum hydraulic fluid in
volume 160.
Still referring to FIG. 1, the hydraulic delay 112 has one or more
fluid ports 143 that provide fluid communication between the uphole
and the downhole ends of the hydraulic delay 112. Within the fluid
port 143 there is a single orifice flow restrictor 134, such as a
JEVA jet, that meters the flow of the hydraulic fluid as it moves
from the downhole side of the hydraulic delay 112 defined by volume
160 to the uphole side. The flow of hydraulic fluid through the
fluid port 143 is caused by the motion of the hydraulic delay 112
downhole.
Within the firing head 115 there is a ball retaining rod 146 held
in place by one or more shear pins 127. The rod 146 has an undercut
147. The rod 146 is coupled to the firing pin 148. Balls 125
provide friction holding the rod 146 in place. The rod 146 is
slidable engaged with the rod retainer 156. When the rod 146 slides
downhole within the firing head 115 the undercut 147 reaches the
balls 125, causing the friction holding the rod 146 in place to
release, thus allowing the rod 146, and hence the firing pin 148,
to then quickly travel downhole, impacting the percussion detonator
128. The impact of the firing pin 148 with the percussion detonator
128 ignites a booster coupled to a detonating cord located in the
bore 157. This detonating cord is connected to a second perforating
gun coupled downhole of the firing head 115 via sub 113.
Still referring to FIG. 1, the detonation of the first perforating
gun located above the time delay sub 100 will result with the end
of the detonating cord and booster igniting within the alignment
insert 109. The force from the exploding booster and detonating
cord will push the communication piston 107 downward, thus
breaching the break plugs 135. This results in downhole fluids
entering the majority of the third bore 155. The wellbore fluid
then acts on the working piston 101, shearing pins 132 forcibly
sliding the working piston 101 downward. Since the working piston
101 is coupled to the middle rod 105, which is coupled to the
hydraulic delay 112, this results in the hydraulic delay 112 begins
moving downward against the hydraulic fluid in volume 160.
As the hydraulic delay 112 moves downhole, the hydraulic fluid in
volume 160 is forced through the port 143 with the flow rate
controlled the orifice flow restrictor 134, in this example a JEVA
style jet. The metering effect of the JEVA style jet is what causes
the time delay between the first perforating gun and the second
perforating gun.
A fully activated hydraulic variable time delay sub 100 is shown in
FIG. 2. Within the communication sub 106 a booster has been fired
in the alignment insert 109 within the first bore 153, compromising
the shear groove 110 and forcing the communication piston 133 out
of bore 154 and through the break plugs 135. The rupturing of break
plugs 135 puts the third bore 155 in fluid communication with the
wellbore via ports 107.
Still referring to FIG. 2, the meter sub 102 coupled below the
communication sub 106 has the working piston 101 forced fully
downhole within the working piston bore 170. This downward movement
by working piston 101 has forced the middle rod 105, hydraulic
delay 112, and the bottom rod 104 to slide fully downhole the inner
bore 145 of the meter sub 102. Volume 160 is completely compressed
and a second volume 161 has been created by hydraulic delay 112,
middle rod 105, and sleeve 111. The hydraulic fluid has been
largely forced out of volume 160 through the metering orifice 134
located in thru bore 143. Pins 132 that were holding the sleeve 111
to the hydraulic delay 112 have been sheared.
Within the firing head housing 115 coupled below the meter sub 102,
ball retaining rod 146 slideably engaged with the rod retainer 156,
has sheared pins 127. The undercut 147 have released balls 125,
thus allowing the rod 146, and hence the firing pin 148, to travel
downhole and impact percussion detonator 128. The impact of the
firing pin 148 with the percussion detonator 128 will have ignited
a booster coupled to a detonating cord located in the bore 157.
This detonating cord is connected to a second perforating gun
coupled downhole of the firing head 115 via sub 113. Thus the
second perforating gun has been fired at some desired delay of time
after the first perforating gun has been fired. The desired delay
can be determined by the combination of the size of orifice 134 and
the hydraulic fluid.
An example embodiment is shown in FIG. 3 of a hydraulic variable
time delay sub 200. This sub performs the task of a pyrotechnic
delay fuse, but instead by using mechanical motion instead of a
chemical reaction. In this design there is a communication sub 206
with outer surface 250 is coupled to and located below a first
perforating gun. An alignment insert 209 that is slidably disposed
in the first bore 253 of the communication sub 206 accepts the end
of a detonating cord with a booster from the first perforating gun.
A shear grooved cap 210 is located between the alignment insert 209
and the communication piston 270. Communication piston 270 has a
first cylindrical portion 251 slidably disposed within the second
bore 254 of the communication sub 206. The second cylindrical
portion 252 of the communication piston 270 is slidably engaged
with the third bore 255 of the communication sub 206. The
communication sub 206 has one of more ports 240 that put the third
bore 255 in fluid communication with the wellbore surround outer
surface 250. O-rings and backup rings prevent the downhole fluids
from entering the majority of the third bore 255 when the
communication piston 270 is in its initial starting position. The
second cylindrical portion 252 has one or more piston ports 241,
which in this example are two thru holes located perpendicular to
each other about the center axis of the hydraulic variable time
delay sub 200. The piston ports 241 puts the third bore 255 in
fluid communication with the inner piston bore 244.
A meter sub 202 is coupled below the communication sub 206. The
meter sub 202 houses a working piston 233 threaded to a middle rod
205 which is further threaded to a hydraulic delay 212, which is
then further threaded to a bottom rod 204. This allows for the
working piston 233, middle rod 205, hydraulic delay 212, and the
bottom rod 204 to slide upwards and downwards in unison within the
inner bore 245 of the meter sub 202. A firing head housing 215 is
coupled below the meter sub 202. The volume defined by the
hydraulic delay 212, the hydraulic fluid bore 245, the bottom rod
204, and the firing head housing 215 create a hydraulic fluid
chamber 245 storing hydraulic fluid. Initially installed, the
combination of working piston 233, middle rod 205, hydraulic delay
212, and the bottom rod 204 are located as far upward as possible
to store the maximum hydraulic fluid.
Still referring to FIG. 3, the hydraulic delay 212 has one or more
fluid ports 243 that provide fluid communication between the uphole
and the downhole ends of the hydraulic delay 212. Within the fluid
port 243 there is a single orifice flow restrictor, such as a JEVA
jet, that meters the flow of the hydraulic fluid as it moves from
the downhole side of the hydraulic delay 212 to the uphole side.
The fluid of hydraulic fluid through the fluid port 243 is caused
by the motion of the hydraulic delay 212 downwards.
Within the firing head 215 there is a ball retaining rod 246 held
in place by one or more shear pins 227. The rod 246 has an undercut
247. The rod 246 is coupled to the firing pin 248 contained within
firing pin retainer 249. Balls 225 provide friction holding the rod
246 in place. The rod 246 is slidably engaged with the rod retainer
256. When the rod 246 slides downhole within the firing head 215
the undercut 247 reaches the balls 225, causing the friction
holding the rod 246 in place to release, thus allowing the rod 246,
and hence the firing pin 248, to then quickly travel downhole until
it impacts the percussion detonator 228. The impact of the firing
pin 248 with the percussion detonator 228 ignites a booster coupled
to a detonating cord located in the bore 257. This detonating cord
is connected to a second perforating gun coupled downhole of the
firing head 215.
Still referring to FIG. 3, the detonation of the first perforating
gun located above the time delay sub 200 will result with the end
of the detonating cord and booster igniting within the alignment
insert 209. The force from the exploding booster and detonating
cord will push the communication piston 270 downward, resulting in
the o-rings and backup rings moving below the ports 240. This
results in downhole fluids entering the majority of the third bore
255. The downhole fluid will then enter the piston ports 241 and
fill the inner piston bore 244. The wellbore fluid then acts on the
working piston 233, forcibly sliding it downward. Since the working
piston 233 is coupled to the middle rod 205, which is coupled to
the hydraulic delay 212, this results in the hydraulic delay 212
begins moving downward against the hydraulic fluid.
As the hydraulic delay 212 moves downhole, the hydraulic fluid is
forced through the port 243 with the flow rate controlled by a JEVA
style jet. The metering effect of the hydraulic fluid is what
causes the time delay between the first perforating gun and the
second perforating gun.
In an alternative embodiment a frangible disk may be used instead
of the break plugs as shown in the example embodiments.
The benefits of using a mechanical delay rather than a pyrotechnic
delay fuse may include that it is easier to ship since there are no
explosive components, it is reusable because the mechanical delay
is not damaged by a pyrotechnic, and it is easily variable because
different JEVA jets can be used to provide different delay
times.
Although the invention has been described in terms of embodiments
which are set forth in detail, it should be understood that this is
by illustration only and that the invention is not necessarily
limited thereto. For example, terms such as upper and lower or top
and bottom can be substituted with uphole and downhole,
respectfully. Top and bottom could be left and right, respectively.
Uphole and downhole could be shown in figures as left and right,
respectively, or top and bottom, respectively. Generally downhole
tools initially enter the borehole in a vertical orientation, but
since some boreholes end up horizontal, the orientation of the tool
may change. In that case downhole, lower, or bottom is generally a
component in the tool string that enters the borehole before a
component referred to as uphole, upper, or top, relatively
speaking. The first housing and second housing may be top housing
and bottom housing, respectfully. In a gun to gun delay such as
described herein, the first gun may be the uphole gun or the
downhole gun, same for the second gun, and the uphole or downhole
references can be swapped as they are merely used to describe the
location relationship of the various components. Terms like
wellbore, borehole, well, bore, oil well, and other alternatives
may be used synonymously. Terms like tool string, tool, perforating
gun string, gun string, or downhole tools, and other alternatives
may be used synonymously. The alternative embodiments and operating
techniques will become apparent to those of ordinary skill in the
art in view of the present disclosure. Accordingly, modifications
of the invention are contemplated which may be made without
departing from the spirit of the claimed invention.
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